1. Field of the Invention
This invention relates generally to an improved electromagnetic switching apparatus including electrical insulation means for interrupting the electrical connection between the fixed contact elements of the switching apparatus and a plurality of contact bridges having movable contacts mounted thereon.
2. Description of the Prior Art
Electromagnetic switching apparatus using contacts which are selectably changeable into "break" and "make" contacts, and comprising a plurality of electrically-interconnected fixed contact elements which cooperate with a plurality of contact bridges on both sides and at each end thereof and electrical insulation means for interrupting the electrical connection between the fixed contact elements and the contact bridges in a pair of end positions of a contact bridge carrier on which the contact bridges are mounted, are known in the art.
For example, in the electromagnetic switching apparatus described in German Auslegeschrift No. 1,490,042, electrical insulation caps are moved into contact with a contact bridge or are designed also as changeable insulation parts which are disposed at the contact point between the fixed contact element and the contact bridge of the switching apparatus. The disadvantage of such an arrangement is that wear at the electrical insulation parts or other effects related to the insulation parts cannot be prevented, and such wear and effects have an adverse effect on the contact surfaces of the fixed contact elements or the contact bridges. As a result, after the insulation caps are changed, the making of the contact as well as the service life of the contact is adversely effected.